Arrangements and methods for controlled flow rate of pneumatic actuated valves

An actuated valve assembly comprising:

• a valve including a valve body defining a flow path and a valve element axially movable to selectively control fluid flow through the valve flow path;
• an actuator assembled with the valve, the actuator comprising:
• a housing defining an inlet port;
• a piston disposed within the housing, wherein the piston is operatively connected with the valve element for axial movement of the valve element;
• a return spring disposed within the housing and configured to apply a first biasing force to the piston to move the piston toward a spring return position;
• and
• an elastically deformable element;
• wherein a first fluid pressure applied to the inlet port moves the piston against the first biasing force of the return spring to a first actuated position in which the piston indirectly engages a stop portion of the housing through at least the elastically deformable element;
• wherein a second fluid pressure, greater than the first fluid pressure, applied to the inlet port moves the piston against a second biasing force of the elastically deformable element to compress the elastically deformable element and to move the piston to a second actuated position beyond the first actuated position;
• wherein the elastically deformable element has a spring rate that provides for proportional incremental movement of the piston between the first actuated position and the second actuated position in response to incremental increases in fluid pressure applied to the inlet port between the first fluid pressure and the second fluid pressure;
• and
• wherein the piston comprises a stem portion extending into the inlet port of the housing, and a disk portion extending radially outward from the stem portion, and wherein the stop portion is defined by an internal surface of the inlet port, and the elastically deformable element is disposed between the internal surface of the inlet port and an end portion of the stem portion.

An actuated valve assembly comprising:

• a valve including a valve body defining a flow path and a valve element axially movable to selectively control fluid flow through the valve flow path;
• an actuator assembled with the valve, the actuator comprising:
• a housing defining an inlet port;
• a piston disposed within the housing, wherein the piston is operatively connected with the valve element for axial movement of the valve element;
• a return spring disposed within the housing and configured to apply a first biasing force to the piston to move the piston toward a spring return position;
• and
• an elastically deformable element;
• wherein a first fluid pressure applied to the inlet port moves the piston against the first biasing force of the return spring to a first actuated position in which the piston indirectly engages a stop portion of the housing through at least the elastically deformable element;
• wherein a second fluid pressure, greater than the first fluid pressure, applied to the inlet port moves the piston against a second biasing force of the elastically deformable element to compress the elastically deformable element and to move the piston to a second actuated position beyond the first actuated position;
• wherein the elastically deformable element has a spring rate that provides for proportional incremental movement of the piston between the first actuated position and the second actuated position in response to incremental increases in fluid pressure applied to the inlet port between the first fluid pressure and the second fluid pressure;
• and
• wherein the piston is a first piston, and wherein the actuator further comprises a second piston disposed within the housing, wherein the first fluid pressure applied to the inlet port moves the second piston against the first biasing force of the return spring to a first actuated position of the second piston, and wherein the stop portion is defined by an end face of the inlet port, and the elastically deformable element is disposed between the first piston and the second piston.